Who should not take Theacrine

Theacrine is sold as a food supplement, and the label rarely has a full list of contraindications. However, it is a stimulating substance, close to caffeine, that stays in the body for a long time. For some people even a “mild” stimulant can be dangerous. The editorial team examined who should give up theacrine or use it only after consulting a doctor.

Where the contraindications come from

Theacrine is a purine alkaloid, structurally close to caffeine. Animal studies have shown its interaction with adenosine and dopamine receptors (Feduccia et al., 2012). This means that its effects touch the same systems as the action of caffeine: the nervous, cardiovascular and sleep-regulation systems.

Safety studies in humans, in particular the work of Taylor et al. (2016), were conducted in healthy adults without serious diseases. The neutral results regarding pulse and blood pressure in this group are not automatically transferred to people with chronic diseases.

Because of the absence of special studies in vulnerable groups, the contraindications for theacrine are formulated by analogy with caffeine and other stimulants and taking physiology into account. This approach is a standard practice of caution for little-studied substances.

It is also important that theacrine is rarely consumed on its own. Most products contain caffeine and other stimulants, so the contraindications of these components effectively extend to the whole product.

Cardiovascular diseases

People with heart rhythm disorders — atrial fibrillation, frequent extrasystoles, long-QT-interval syndromes — have an increased risk of complications from any stimulants. Even if theacrine on its own acts more mildly than caffeine, in combined products the total stimulation can provoke an arrhythmia.

Uncontrolled arterial hypertension is another substantial restriction. Caffeine in people without tolerance is capable of temporarily raising blood pressure, and theacrine most often arrives together with it. For people with already high blood pressure such additional strain is undesirable.

Coronary heart disease, a previous heart attack, heart failure, cardiomyopathies are conditions in which any increase in the load on the heart should be assessed by a cardiologist. Self-administration of stimulating supplements here is impermissible.

Separately, it is worth mentioning athletes with undiagnosed heart diseases. Sudden cardiac events during exertion are often associated with hidden defects, and stimulants combined with intense work can be an additional trigger. Complaints of chest pain, fainting or interruptions in the heart's work during training are a reason to get examined, not to take supplements.

The nervous system, psyche and sleep

People with generalized anxiety disorder, panic attacks or social anxiety often tolerate stimulants poorly. Caffeine in sensitive people is capable of provoking panic attacks, and it is logical to expect a similar reaction to related substances.

Chronic insomnia is another reason to give up theacrine. The substance stays in the body for a long time, and when combined with caffeine its elimination slows (He et al., 2017). Even morning intake may affect falling asleep in sensitive people.

Bipolar disorder and other conditions associated with the dopamine system require special caution. Animal data indicate a dopaminergic component of theacrine's action, and stimulants in general are capable of affecting the course of such disorders.

Epilepsy is a condition in which any stimulants should be discussed with a neurologist. There are no direct data on theacrine, but high doses of methylxanthines can lower the seizure threshold.

• Anxiety and panic disorders.
• Chronic insomnia.
• Bipolar disorder and other mental conditions — only by a doctor's decision.
• Epilepsy — only after consulting a neurologist.

Pregnancy, children and other special groups

During pregnancy the metabolism of caffeine slows substantially, and separate restrictions have been established for it. For theacrine there are no data on fetal safety at all, so pregnant and breastfeeding women should avoid it.

Children and adolescents are especially sensitive to stimulants. Theacrine has not been studied for them, and energy drinks and pre-workout complexes are not intended for this age group at all.

People with liver diseases may metabolize purine alkaloids more slowly, which prolongs their action. People with hyperthyroidism already have increased stimulation of the cardiovascular and nervous systems, and additional stimulants can intensify tachycardia and anxiety.

People with peptic ulcer disease or gastroesophageal reflux should take into account that caffeine, with which theacrine is usually combined, can intensify symptoms. Caution is also needed for elderly people, who often take several medications at once.

Interactions with medications and other stimulants

The most important interaction is with caffeine: it increases the exposure to theacrine. The total stimulant load should be assessed taking all sources into account, and for caffeine one should be guided by the EFSA recommendations — up to 400 mg per day for healthy adults.

Other stimulants — synephrine, yohimbine, amphetamine-like compounds, medications for treating ADHD — intensify the effect on the heart and nervous system. Combining them with theacrine without medical supervision is not advisable.

Monoamine oxidase inhibitors, some antidepressants and drugs that affect the dopamine system may theoretically interact with theacrine. There are no direct studies, so the decision should be made by a doctor.

Medications that affect heart rhythm and blood pressure, as well as drugs whose metabolism depends on the liver enzymes that break down methylxanthines (for example, some fluoroquinolone antibiotics slow the elimination of caffeine), are a reason to consult before use.

Editorial conclusions

Theacrine is a stimulant, and its contraindications are similar to those of caffeine: heart diseases, uncontrolled hypertension, anxiety disorders, insomnia, pregnancy and childhood.

The neutral results of safety studies concern healthy adults and do not extend to vulnerable groups, for which there are no data.

Special attention should be paid to the total stimulant load and interaction with medications, since theacrine most often arrives as part of complex products with caffeine.

We also recommend reading “Side effects of Theacrine,” “Theacrine: dosage forms and which to choose” and “How to take Theacrine: dosage, timing, duration.”

References

1. Taylor L, Mumford P, Roberts M, et al. Safety of TeaCrine®, a non-habituating, naturally-occurring purine alkaloid over eight weeks of continuous use. J Int Soc Sports Nutr. 2016;13:2.
2. Feduccia AA, Wang Y, Simms JA, et al. Locomotor activation by theacrine, a purine alkaloid structurally similar to caffeine: involvement of adenosine and dopamine receptors. Pharmacol Biochem Behav. 2012;102(2):241–248.
3. He H, Ma D, Crone LB, et al. Assessment of the drug–drug interaction potential between theacrine and caffeine in humans. J Caffeine Res. 2017;7(3):95–102.
4. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). Scientific opinion on the safety of caffeine. EFSA J. 2015;13(5):4102.
5. Guest NS, VanDusseldorp TA, Nelson MT, et al. International society of sports nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr. 2021;18(1):1.
6. Nehlig A. Interindividual differences in caffeine metabolism and factors driving caffeine consumption. Pharmacol Rev. 2018;70(2):384–411.